BVE: Question - British signalling practice

[nigelb]

Question for the group - when track is doubled, Do British railways use signals on the right hand track, so that if a section of the normal left hand track is closed for maintenance or some other reason, the train can use the right hand track and have facing signals? How about LUL? If not, how is control maintained when it is necessary to route trains in emergency situations? I imagine the branch right would have a feather juntion signal, but what about signals after that on the "wrong" track, and the brach back to the left (ground signal perhaps?)

Just curious since many BVE routes appear to omit this, perhaps for simplicity or perhaps because it is actual practice.

This is not a criticism of any BVE routes at all, just an observation and a question.

[TomBeevers2000]

RE: Question - British signalling practice

Only some bits. Not on LUL at all. When one line is closed Pilot Working is introduced. Trains are stopped at the entrance to the forced single line section and are not allowed to proceed until the Pilot Man for that section is in the cab. Therefore only one train can be in the single line section as there's only one pilotman. Some newer sections of line are bi-di signalled though. I think they install bi-di equiptment if one line is to be closed for a long time. IIRC this happened on the Picc line and Northern line between Alperton and South Harrow and Totteridge and Barnet respectively a few years ago (embankment failure).

--
Tom Beevers

http://brj.rr.nu

[Bill_Veloz]

RE: Question - British signalling practice

A complicated question with no easy answer.

Bidirectional signalling is tracks capable of running trains in both directions on the same piece of line. Certainly in some areas bidirectional is used as a matter of routine ie Paddington - Ladbroke Grove (about 3 miles)where there are six lines used in both directions and under the control of automatic route setting which consists of three computers talking to each other and agreeing a route before it sets itself automatically. Each line can be over-ridden by the Signaller.
.
In rural areas ie Didcot - Swindon where there are two lines there is bi-directional running which is used in an emergency or for planned track work. In this either the 'down' (away from London, or the 'up' (towards London) is converted into the other line to pass trains. It is not used for example for a faster train to overtake a slower moving one. In this area the signals are set up side by side on the same gantries, the line not being used showing a red signal. At the junctions where trains can cross to the other line there are the usual junction indicators ('feathers'). The drivers have to be told in advance of the use of the other line ie 'up' the 'down' line and they travel at a slightly reduced speed. Didcot - Swindon is about 20 miles and is used fairly regularly when things are going wrong. They also have it from Wootton Bassett to Thingley (near Chippenham) and Wootton Bassett towards South Wales. These are rural areas where extensive delays would be caused if it wasn't there.

Use of one line on a two track railway where bidirectional does not exist is a lengthy and time consuming matter involving a lot of men and even more paperwork. It is a situation avoided where possible because it is very unwieldy. Bidirectional makes working over one line easy but is not very widespread here as far as I know. My knowledge is confined to the Great Western main line out of Paddington, it must be existence elsewhere on the british lines.

Hope that helps.

Bill

[nigelb]

RE: Question - British signalling practice

Thanks for your responses guys! Very educational and helpfull!

[kayedj]

RE: Question - British signalling practice

>Use of one line on a two track railway where bidirectional
>does not exist is a lengthy and time consuming matter
>involving a lot of men and even more paperwork. It is a
>situation avoided where possible because it is very
>unwieldy.

what would they do then? have men with flags?

[Bill_Veloz]

RE: Question - British signalling practice

>what would they do then? have men with flags?

Short answer - yes.

Putting in single line working over one line of a two line route in very time consuming and manpower hungry. Here's how it works.

A to B is a two track railway 15 miles apart. One line is out of use so trains in both directions have to use the other line.

Firstly a Pilotman is appointed. He acts as the authority to run trains in each direction and actually has to ride on each train to confirm that that train has the right to be on the line.

Before that train can move he must confirm with the controlling Signaller that he wishes that train to run.

The Pilotman and the Signaller must each fill out a form so that there is a clear understanding of what is to happen. The instructions must be read out to each other to make sure that it is all understood.

At this point the train may now proceed to the start of the single line working where there will be a handsignaller who will confirm with the Pilotman that the route is correctly set and that the train may proceed into the section.

Having passed over the single line and the train is ready to run normally the Pilotman must now cancel that authority with the Signaller and apply for the next train to move onto the single line.

If there are several trains to move in the same direction the Pilotman may authorise each train to proceed without him, but he must ride on the last train through. Each of these Drivers will have been given a form authorising him to run on the single line, and he will have been given clear verbal instructions about what he is to do. He must repeat these instructions to the Pilotman so that there is a clear understanding. Before that the Pilotman will have filled out a form with the Signaller and come to an understanding with him about what is to happen.

Only one train at a time is permitted on the single line even if there are several waiting to go in the same direction.

That it then - I think! - and as briefly as possible.

We have had single line working on the Reading - Basingstoke line before now and it leads to absolute chaos. Thames have two trains per hour in each direction, Virgin the same, SouthWest Trains one each way and various freights. For single line working the track occupation is one train in each direction an hour so you can see the chaos that it causes.

In addition to the Pilotman, a handsignaller is required at the start of each section of single line, and there must be an attendant at any unmanned level crossings which are not full barrier.

Hope thats not too confusing. Wouldn't bidirectional make it easier!

Bill

[Ex_Connex]

RE: Question - British signalling practice

Not sure if they have these on other regions, but on the South East and Central they have what are called SIMBIDs (Simplified BiDirectional) They are Between Sevenoaks and Ashford (Rougly speaking) and Balcombe and Brighton. They are used for Double tracks of high volume of traffic in case of a Train Failure etc. They are permanent features, you are signalled in and then only again on the other track with a single yellow then routed out of the SIMBID to get out back on to normal running. AWS has cancelled signs and line speed is usally 50mph.

Thats very basically speaking, a few lines to describe what takes a couple of days in a classroom to learn.

Nothing to stop a route developer putting in a SIMBID in to whatever route they are designing. Would also be interesting to find somebody brave enuff to take on a route that has Temporary Block Working as an option, I wonder how many mistakes peeps would make

[nigelb]

RE: Question - British signalling practice

Sounds a little easier than the method with the flags, pilotman and paperwork even if it does require classrrom time.

Thanks for your response!